Conventionally, in order to cut hard and brittle materials such as silicon single crystal, there has been used a cutting agent comprising an abrasive grain such as silicon carbide (SiC) dispersed in cutting liquid, and this cutting agent is supplied to a contact portion between a cutting device and work material to thereby obtain metal sheets of several tens to several thousands .mu.m by slicing the work material thin.
Also, in the case of precision cutting using, for example, a multi-wire sawing device, the cutting is usually performed as follows: That is, in the multi-wire saw cutting device, wire is wound many times around a multi-grooved guide roller made of high molecular weight material, obtained by cutting with high precision to be reciprocated by a driving motor. This reciprocating wire is pressed against the work material while an adequate cutting load is being applied thereto to perform cutting by a cutting operation while the cutting agent is being supplied to the contact portion. Since the reciprocating wire is gradually worn as the work material is cut, the wire is wound up by a torque motor, and a new wire is supplied by a geared motor.
As the foregoing cutting agent, there have been used an oil cutting agent prepared by adding additives or the like to mineral oil as the base, a glycol cutting agent mainly composed of polyethylene glycol or polypropylene glycol, and an aqueous cutting agent mainly composed of an aqueous solution of a surface-active agent.
However, the conventional oil base cutting agents had the following problem: That is, the cutting agents mainly composed of mineral oil have the advantages that they are excellent in lubricating properties, and have good cut surface of the work material, and good cutting performance, but are inferior in cooling performance. Therefore, the conventional oil base cutting agents had the problem that the operating efficiency is decreased because the temperature at a contact portion increases during an operation to generate oil mist, an operator gets burned in a dismantling operation for the work material after the termination of a cutting operation, or a fire can also occur.
Also, when the work material, the operator and equipment have been contaminated by the cutting agents, an organic solvent cleaning fluid such as trichloroethane, methylene chloride or the like is required to remove the pollution. Since, however, the organic solvent cleaning fluid causes carcinogenesis or air pollution, there has also been the problem of waste treatment that it cannot be scrapped unless some disposal is performed for the cleaning discharge.
Also, in order to solve such conventional problems on the oil base cutting agent, the aqueous cutting agent mainly composed of the foregoing glycol cutting agent or aqueous solution of a surface-active agent has also been studied, but the viscosity stability during cutting was not sufficient, good cutting performance could not be obtained, and it was inferior in dispersion stability of the abrasive grain, and it could not be sufficiently satisfied.